obj = new HTMLPurifier_ChildDef_Custom('(a,b?,c*,d+,(a,b)*)');
        $this->assertEqual($this->obj->elements, array('a' => true,
            'b' => true, 'c' => true, 'd' => true));
        $this->assertResult('', false);
        $this->assertResult('', false);
        $this->assertResult('');
        $this->assertResult('Dobfoo'.
          'foo');
    }
    public function testNesting()
    {
        $this->obj = new HTMLPurifier_ChildDef_Custom('(a,b,(c|d))+');
        $this->assertEqual($this->obj->elements, array('a' => true,
            'b' => true, 'c' => true, 'd' => true));
        $this->assertResult('', false);
        $this->assertResult('');
        $this->assertResult('', false);
    }
    public function testNestedEitherOr()
    {
        $this->obj = new HTMLPurifier_ChildDef_Custom('b,(a|(c|d))+');
        $this->assertEqual($this->obj->elements, array('a' => true,
            'b' => true, 'c' => true, 'd' => true));
        $this->assertResult('', false);
        $this->assertResult('');
        $this->assertResult('');
        $this->assertResult('');
        $this->assertResult('', false);
    }
    public function testNestedQuantifier()
    {
        $this->obj = new HTMLPurifier_ChildDef_Custom('(b,c+)*');
        $this->assertEqual($this->obj->elements, array('b' => true, 'c' => true));
        $this->assertResult('');
        $this->assertResult('');
        $this->assertResult('');
        $this->assertResult('');
        $this->assertResult('', false);
    }
    public function testEitherOr()
    {
        $this->obj = new HTMLPurifier_ChildDef_Custom('a|b');
        $this->assertEqual($this->obj->elements, array('a' => true, 'b' => true));
        $this->assertResult('', false);
        $this->assertResult('');
        $this->assertResult('');
        $this->assertResult('', false);
    }
    public function testCommafication()
    {
        $this->obj = new HTMLPurifier_ChildDef_Custom('a,b');
        $this->assertEqual($this->obj->elements, array('a' => true, 'b' => true));
        $this->assertResult('');
        $this->assertResult('